1. Field of the Invention
The present invention relates to a device for feeding of purging, flushing and degraphitizing air to the pipes for rich gas running to individual heating walls of coke ovens, where there is to be provided initially the release of a comparably small cross-section aperture for the purging air and successively the release of a larger cross-section aperture for the degraphitizing air.
2. Brief Description of the Background of the Invention Including Prior Art
Purging air serves as is known for removal of amounts of residual gas still in the pipe after shut-off of the feeding of rich gas. The thereafter fed degraphitizing air is to effect a burning off of the graphite deposits formed in the nozzles for rich gas and in the pipe for rich gas. However, it is in this context required to adjust accurately the amount of purging and flushing air in order to avoid deflagrations of inflammable and/or explosive mixtures.
In conventional devices of this kind a box-shaped provision is attached to the pipe for rich gas or respectively to an air feeding pipe connected to the pipe for rich gas, which box-shaped provision is provided with a flap. Usually this flap is connected via a chain to a rod system, which can be moved in a longitudinal direction actuated by an actuating provision (hydraulic jack or the like). In a first motion of the rod system thereby the flap is lifted up by an exactly preset amount and thereby releases the opening cross-section for the purging air required. In a later further motion of the rod system the flap is then completely lifted such that the full cross-section is available for the flowing in of degraphitizing air. The closing of the flap is provided by an opposite motion of the rod system and by the self-weight of the flap after termination of the degraphitizing process.
It has now been found that in the course of the operation of the coke oven battery there are frequently changes in the length of the rod system based on the variations in temperature. The changes in the length lead frequently to changes in the aperture width of the flap and as a result deviations in the amount of purging air occur. This can lead to the deflagrations mentioned above, which, unless readjustments are provided in time, result in leaks or thrown out nozzles.